Such radial bushings are already known in the prior art.
A particular object of the present invention is to further improve such bushings.
To this end, according to the invention, in a radial bushing of the kind in question, said radial stop is positioned on said outer element between said arms, and comprises an arch having extremities joined to said outer element and a top oriented towards said rigid element, said arch defining with said outer element a tubular cavity.
By means of these dispositions, the operating life and performance of such bushings is increased.
In preferred embodiments, it is possible to use one or more of the following dispositions:
the arch is integrally formed with the outer element, and preferably extends in a substantially parallel direction to the central axis;
the arch is substantially shaped in the form of a shape selected from the group consisting of: triangular shaped, trapezoidal shaped, rectangular shaped, arc shaped; said arch further comprising an axe of symmetry oriented towards the rigid element;
the tubular cavity is filled with an elastomer;
the elastomer filing the tubular cavity is integrally formed with the elastomer body forming the elastomer arms;
the arch has a cut-out therein allowing elastomer in the tubular cavity to connect with the elastomer body;
the elastomer filling the tubular cavity is of different properties than the elastomer constituting the elastomer arms;
the a least one radial stop is also constructed as an axial stop by protruding elastomer axially from the tubular cavity;
the outer annular element is made from a material selected from the group consisting of: synthetic compound, fibreglass, fibreglass reinforced plastic, metallic compound (especially aluminium);
a plurality of radial stops, each comprising an arch, are provided;
at least two of the arches are of different shape;
the radial stops exhibit different radial stiffness.
A further advantage of this invention is that less material is needed to manufacture such a device, therefore they are cheaper to produce.
Besides, another object of the present invention is a method of manufacturing a radially flexible bushing including an inner rigid element surrounded the steps of:
molding the outer annular element together with at least one arch having extremities joined to said outer element and a top oriented towards said inner rigid element, said arch defining with said outer element a tubular cavity,
molding an elastomer body which adherently attaches the inner periphery of said outer element, said elastomer body comprising a plurality of spaced-apart arms extending radially from said inner rigid element to said outer element, and
placing said inner element such that the elastomer arms attach said inner element and such that the arch provides at least one radial stop, positioned on the annular element between said arms, for limiting the radial displacement of said inner rigid element.
In a variant of the above method:                said outer element and said elastomer body are bi-injection molded, the bi-injection steps comprising:        
(a) a first step of injecting a first material, thereby creating said outer annular element and said at least one arch, and
(b) a second step of injecting a second material, thereby creating said elastomer body;
said inner rigid element is inserted inside said elastomer body, thereby radially pre-compressing said elastomer arms;
said tubular cavity is filled in the same operation as used to mold said elastomer arms;
said tubular cavity is filled in a subsequent operation as used to mold said elastomer arms;
wherein axial stops are extruded in elastomer from the tubular cavity, in the same operation as when said tubular cavity is filled.
These dispositions lead to a device with lower inherent operating stresses and therefore longer fatigue life, and in particular to one with no localised high stress zones during normal operating modes.